i18n: added JS utils for translation.

Gruntfile.js

@@ -19,6 +19,7 @@ module.exports = function(grunt) {
           '<%= dirs.js.src %>/mousetrap.js',
           '<%= dirs.js.src %>/moment.js',
           '<%= dirs.js.src %>/appenlight-client-0.4.1.min.js',
+          '<%= dirs.js.src %>/i18n_utils.js',
 
           // Plugins
           '<%= dirs.js.src %>/plugins/jquery.pjax.js',

rhodecode/public/js/src/i18n_utils.js

@@ -0,0 +1,36 @@
+// # Copyright (C) 2016-2016  RhodeCode GmbH
+// #
+// # This program is free software: you can redistribute it and/or modify
+// # it under the terms of the GNU Affero General Public License, version 3
+// # (only), as published by the Free Software Foundation.
+// #
+// # This program is distributed in the hope that it will be useful,
+// # but WITHOUT ANY WARRANTY; without even the implied warranty of
+// # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// # GNU General Public License for more details.
+// #
+// # You should have received a copy of the GNU Affero General Public License
+// # along with this program.  If not, see <http://www.gnu.org/licenses/>.
+// #
+// # This program is dual-licensed. If you wish to learn more about the
+// # RhodeCode Enterprise Edition, including its added features, Support services,
+// # and proprietary license terms, please see https://rhodecode.com/licenses/
+
+i18nLog = Logger.get('i18n');
+
+var _gettext = function (s) {
+    if (_TM.hasOwnProperty(s)) {
+        return _TM[s];
+    }
+    i18nLog.error(
+        'String `' + s + '` was requested but cannot be ' +
+        'found in translation table');
+    return s
+};
+
+var _ngettext = function (singular, plural, n) {
+    if (n === 1) {
+        return _gettext(singular)
+    }
+    return _gettext(plural)
+};